Summary of this article
Signs of completed implantation may include implantation bleeding and implantation pain, which usually appear in the third week to a week of pregnancy and not necessarily in everyone. Symptoms of implantation include changes in discharge, implantation bleeding, anaemia and cold-like symptoms, which vary from person to person and are no different for IVF than for normal implantation. Pregnancy tests should be used from the fourth week of pregnancy onwards, and if a positive test occurs, consider seeing an obstetrician. However, if there is bleeding, it is important to consult a hospital as soon as possible.
Introduction
Bleeding and pain at a time when you are eagerly awaiting conception can be worrying. But it could also be a happy sign that implantation is complete, meaning that a pregnancy has taken place. In this article, we will explain in detail about the signs of implantation, what implantation is, what the symptoms are, when they appear and what to do afterwards.
What is implantation?
Implantation refers to the fertilised egg that is fertilised by sperm and egg after sexual intercourse, attaches itself to the surface of the uterus (endometrium), takes root and burrows into the endometrium. Implantation results in a pregnancy. When the ovulated egg is fertilised by a sperm, it becomes a fertilised egg. The fertilised egg repeats cell division and becomes an embryo over a period of about one week to 10 days, before reaching the uterus. If the fertilised egg (embryo) grows smoothly, pregnancy can be confirmed around 10 days after implantation.
What are signs of completed implantation?
Unfortunately, there is no one sign of completed implantation that is always seen in everyone. There are a number of symptoms that may be felt around the time implantation occurs, but just because you are asymptomatic does not mean that implantation has not occurred.
The most common signs of completed implantation are implantation bleeding and implantation pain. These are explained in more detail below.
When is implantation complete signalled?
Signs of completed implantation appear around the beginning of the third week of pregnancy, about one week into the pregnancy. This is related to the way the weeks of pregnancy are counted.
When counting the number of weeks of pregnancy, instead of counting from conception (after sexual intercourse), the day on which the last menstrual period began is counted as week 0, day 0. Ovulation occurs about two weeks after the start of menstruation, so at the time of fertilisation you are already two weeks pregnant. Implantation occurs about a week after that, which means that at the time of implantation in clinical studies, the pregnancy is 3 weeks.
Symptoms seen at the time of implantation
In addition to fertilisation, a woman’s body undergoes many changes during implantation. This section describes the characteristic physical changes that occur during implantation.
Changes in haemorrhage
The amount and nature of discharge can be affected by hormones. Fertilisation increases the amount of oestrogen, which makes it easier for the discharge to increase. Clinical studies suggest that changes in discharge may contribute to implantation.
In addition, implantation changes the vaginal pH, which can change the consistency of the discharge. The colour often changes from translucent to milky white or light brown. A white discharge that is more watery and silky than usual may also occur.
Implantation bleeding
One of the most common symptoms after implantation is implantation bleeding. In clinical studies, implantation bleeding is one sign that implantation is complete.
The endometrium can be damaged when the fertilised egg burrows into the endometrium. This is why a small amount of bleeding may only be seen for a short period of time, around one or two days before or after implantation. Clinical studies suggest that this bleeding is associated with successful implantation.
What is implantation bleeding?
Implantation bleeding is bleeding that occurs at the time of implantation. It occurs at about the same time as or slightly earlier than the expected start of menstruation, so many people mistakenly think that they may be having their period when they see the bleeding.
It is estimated that less than 25% of people are aware of implantation bleeding. The absence of implantation bleeding does not mean that ‘implantation has not occurred’. In clinical studies, the presence or absence of this bleeding is considered to be one clinical factor.
Differences with menstruation
Implantation bleeding and menstruation are easy to mistake as they occur at similar times, but the amount, colour and duration of bleeding usually differ.
Implantation bleeding is often less than the amount of blood loss during menstruation. The colour may be light pink or brown, but it is often mild with blood in the discharge. The duration is usually one to two days, or even three to four days for those who have a prolonged period, and it subsides earlier than menstruation.
However, some people may experience bright red blood that is indistinguishable from menstruation and think they have a ‘normal period’, but it is implantation bleeding and they are actually pregnant.
If symptoms such as heavy bleeding, prolonged bleeding, blood clots or pain in the lower abdomen are observed, there is a possibility of miscarriage or ectopic pregnancy. See an obstetrician and gynaecologist as soon as possible.
Implantation pain
Although not medically proven, the pain felt during implantation is sometimes referred to as implantation pain. Many people experience a prickling, tingling or throbbing abdominal or back pain that is slightly different from menstrual pain, but it can also be a dull ache similar to menstrual pain. Others experience stomach pain and pain in the pubic bone, as well as tension and discomfort in the abdomen and breasts.
Anaemia
In early pregnancy, dizziness and dizziness may occur. These symptoms are related to hormonal imbalance and anaemia. If symptoms are severe, see a doctor as soon as possible.
Cold-like symptoms
Normally, the basal body temperature before menstruation is “0.3-0.5°C higher than in the low-temperature phase”, which is called the “high-temperature phase”.
Just before menstruation, the basal body temperature suddenly drops and enters the low temperature phase.
On the other hand, when implantation occurs and pregnancy is established, the body temperature does not drop and the high temperature phase lasts for more than 17 days. This change in body temperature is caused by an increase in the female hormone progesterone due to pregnancy.
The increase in progesterone may also cause drowsiness and lethargy. This is thought to be the reason why women may feel somewhat cold, have a slight fever, feel tired and chilly after implantation.
Emotional instability
One of the symptoms that may be seen during implantation is emotional instability. When implantation, or pregnancy, takes place, the female hormones oestrogen and progesterone increase. These hormones can cause psychological symptoms such as irritability, drowsiness and lack of energy.
In the case of IVF implantation
In recent years, IVF has become a popular choice for fertility treatment. Is there any difference in the time of implantation when IVF is used compared to natural conception?
IVF pregnancy outcomes
In in vitro fertilisation, an egg is extracted before ovulation and fertilised with sperm outside the body. The fertilised eggs are incubated for several days and the highest grade embryos are returned to the uterus.
Depending on how long the fertilised eggs are cultured in vitro, they are divided into early embryo transfer and blastocyst transfer.
When early embryos are transferred
In early embryo transfer, the fertilised embryo is cultured for two to three days and the early embryo in the 2- to 8-division stage is returned to the uterus. In early embryo transfer, the embryo implants in the endometrium 4-5 days after transfer and a pregnancy is established.
When a blastocyst is transferred
In blastocyst transfer, the fertilised embryo is cultured for 5-6 days and the embryo that has grown to a blastocyst is returned to the uterus. One or two days after transfer, the embryo implants in the endometrium and a pregnancy is established.
Are there any differences in symptoms from normal implantation?
Just because it is IVF does not mean that it is any different from normal implantation. It may be asymptomatic as in a natural pregnancy, or implantation bleeding and implantation pain may occur.
What to look out for from IVF to implantation
Sexual intercourse should be avoided after implantation as it can stimulate uterine contractions and interfere with implantation. Exercise, in moderation, is not a problem as it improves blood circulation to the uterus and aids implantation, but excessive exercise should be avoided.
After embryo transfer, you may feel anxious and stressed, but try to lead a normal life and try to relax.
What is endometritis causing implantation failure?
Endometritis is an inflammation of the lining of the uterus and is thought to cause implantation failure. Symptoms include mild abdominal pain, painful intercourse and a small amount of genital bleeding, which may be asymptomatic.
If you have had multiple attempts at IVF without successful implantation, you may want to have it checked.
I thought I might be pregnant
If you think you might be pregnant, for example, if your period doesn’t come on time or if you have symptoms that could be a sign of implantation, you should check with an over-the-counter pregnancy test.
When to use a pregnancy test?
Pregnancy tests are used around one week after the expected start of menstruation. Pregnancy tests react only after the fourth week of pregnancy, when the hormones (hCG*1) produced by pregnancy increase, i.e. about 10 days after implantation.
In most cases, there is no positive test in the very early stages of pregnancy, such as the third week. If the test is carried out too early, the test may be negative even though the woman is actually pregnant. It is understandable that you want to find out as soon as possible, but it is important to wait until the right time. Even if the pregnancy test is once negative, it is a good idea to check again if your period has not started after one week.
If the pregnancy test is positive, you should visit an obstetrician and gynaecologist around 5-6 weeks counting from the beginning of your last menstrual period. The obstetrician and gynaecologist will not only check whether you are indeed pregnant, but also examine you in detail for abnormal pregnancy, for example, ectopic pregnancy or miscarriage.
※1 ：Human chorionic gonadotropin
‘I had a positive pregnancy test and now I’m having my period’
If the pregnancy test is positive and there is a small amount of bleeding, it is not menstrual (menstrual) bleeding, but may be implantation bleeding, as discussed above. However, if there is a lot of bleeding or clots of blood, it is not implantation bleeding and there are several other possible causes.
One of these is chemical miscarriage, where fertilisation occurs but implantation does not continue and miscarriage occurs before the foetal sac is confirmed. If a pregnancy test is not used, this is often mistaken for a menstrual period and the woman is unaware that she has had a miscarriage.
Bleeding after a positive pregnancy test can have a variety of causes, so if you experience bleeding, consult a hospital and, if necessary, visit a hospital as soon as possible.
Undergo NIPT once pregnancy is confirmed
Once the pregnancy is confirmed, you can decide when to have NIPT. Generally, the appropriate time for NIPT is after the pregnancy has been confirmed by an ultrasound scan. The amniotic fluid test, which is a definitive diagnosis, can be taken after 15 weeks of pregnancy. Since all test results must be available by 21 weeks’ gestation, when abortion is possible, it is advisable to schedule a NIPT as soon as the pregnancy is confirmed.
Summary
The various signs that are felt in the very early stages of pregnancy regarding implantation described above can be so mild that some people say they did not feel them at all. The absence of signs of implantation or symptoms seen in the very early stages of pregnancy does not mean that you are not pregnant. When menstruation is delayed, it is a good idea to check with a pregnancy test.
Finding out about the pregnancy at the right time allows for planned NIPT and amniotic fluid tests to be carried out. A planned NIPT or amnio test is easier on both the mother and the baby. If you are thinking of having a NIPT when you become pregnant, please consider visiting Hiro Clinic NIPT at the appropriate time for the test.
【References】
- Japanese Society for Reproductive Medicine – Q1. How is pregnancy formed?
Q&A
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QCan implantation be asymptomatic?Of course there is. As discussed above, there are no reliable signs and symptoms of completed implantation in all people. Therefore, it is quite possible to have implantation without any symptoms at all.
If menstruation after sexual intercourse does not come on schedule, check once with a pregnancy test. -
QWhat is the minimum time from fertilisation to implantation?Fertilisation to implantation can take as little as one week.
